The Loch Ness Monster, as it is popularly known, is the world's largest Kelpie. Its favourite shape is that of a Sea serpent. Wizard observers from the International Confederation of Wizards discovered it was a Kelpie when they observed it changing into an otter on the approach of a team of Muggle investigators, then back into a Sea Serpent. The Office of Misinformation has worked diligently, convincing the Muggles that all photographic evidence of "Nessie" is actually fake.[1]

Behind the scenes

It is possible that the kelpie seen in Wonderbook: Book of Spells is intended to be the Loch Ness Monster, as it is rather large, lives in a Scottish loch, and takes the form of what appears to be a sea serpent, rather than the horse form the species generally takes.